When I was wiring in my airhorns, I got lazy and didn't want to run the wire directly to the fuse box (in the cab) into one of the slots for the bigger blue fuses (relays or whatever). Well I succeeded into blowing something and now my running lights, cb, and dash lights do not work. Some how i guess I underestimated the amount of current that flow into the horns just because they were small. Any body know what i fried?

 

Air horns like the $30 deals from the parts store? I had a set and I had them connected to a relay. The wires from one of my original horns activated the relay and when it activated it pulled power directly from the battery.
I believe there is a single fuse that powers what isn't powered on your truck now.

 

+1... Check all the fuses. And wire the horn correctly . lol

 

I done rewired the horn and checked all the fuses. There is only 1 unidentified fuse that confuses me. It might be my mystery fuse. Its big, blue and is unmarked on the label for the fuse box.

 

That's the combination flasher relay.
Sometimes you can't tell that a fuse is blown by just looking at while it is in the fuse box. Did you pull all the fuses associated with what isn't working to get a good look at them? Sometimes the little tab that holds them tight will cook a little and make the fuse not get good contact. Sometimes they will partially blow too and that's enough for them to not allow enough power through.

 

+1...Had a headlight problem, fuse looked good, had continuity, but didn't work.

 

Check to see what circuit the CB is getting power from.

 

Double check the IOD fuse. The one with a black cage over it in the dash fuse panel.

 

Fixed It. It wasnt the IOD or the blue relay, It was a 15 A fuse. The number 1 fuse.

 

Air Horn = Compressor. Ever heard of a compressor that didn't eat gobs of power?

Those little ones ... they're so small they put them on motorcycles sometimes ... use 17 Amps (on a 12V system) and will blow anything under a 20A fuse.